From 7e097b4f4f80311cf9918275bf5a17fb3930ab56 Mon Sep 17 00:00:00 2001
From: Mark McCaskey <mark@wasmer.io>
Date: Wed, 30 Sep 2020 17:47:24 -0700
Subject: [PATCH] Clean up code and add comment

---
 lib/wasi/src/state/builder.rs | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/lib/wasi/src/state/builder.rs b/lib/wasi/src/state/builder.rs
index b3636eecbbb..56fd0cea184 100644
--- a/lib/wasi/src/state/builder.rs
+++ b/lib/wasi/src/state/builder.rs
@@ -438,16 +438,9 @@ impl PreopenDirBuilder {
 
     /// Make this preopened directory appear to the WASI program as `alias`
     pub fn alias(&mut self, alias: &str) -> &mut Self {
-        let alias = if let Some(first_byte) = alias.as_bytes().first() {
-            if *first_byte == b'/' {
-                &alias[1..]
-            } else {
-                alias
-            }
-        } else {
-            alias
-        }
-        .to_string();
+        // We mount at preopened dirs at `/` by default and multiple `/` in a row
+        // are equal to a single `/`.
+        let alias = alias.trim_start_matches(b'/');
         self.alias = Some(alias);
 
         self